EP0348312B2 - Shielded station for a high voltage network - Google Patents

Description

The invention relates to a high shielded post tension, having a metal casing earth and filled with an insulating gas with dielectric strength high, said envelope being subdivided in each bay in different watertight compartments, serving as housing for the apparatus arranged in the electrical circuit between a set of power bars and a departure, each switchgear and / or of sectioning being supervised by two disconnectors of earthing. (see FR-A- 1533481 and EP-A- 0235006).

In a substation, the release disconnectors earth are distributed along the electrical circuit of each span. Some specifications recommend the possibility of isolating the earthing switches earth to authorize electrical tests in different points of the span. These electrical tests consist in injecting a test current into the circuit at level of each disconnector previously isolated, to measure the circuit breaker response time, and to check the characteristics of the transformers as well as elementary voltage drops along the span circuit. Isolation of the whole complicated earthing switches the manufacture of a span, and significantly increases the cost.

The object of the invention is to make a station simplified armored to keep the possibilities test on the electrical circuit.

The position according to the invention is defined according to the characteristics stated in claim 1. It is thus possible in the same span to save insulation on certain disconnectors earthing, without limiting tests electrics on the span.

To isolate an isolatable earthing switch, just disconnect an electrical connection with the earth. Test current injection can be performed then by the isolated terminal of each phase of the disconnector.

The circuit breaker compartment is interposed between a measurement compartment containing a transformer and two games compartments stacked bars each containing a disconnector circuit breaker connection switch to a first busbar, or a second busbar. An isolatable earthing switch is housed in the measuring compartment.

An isolatable earthing switch is also associated with each busbar.

• la figure 1 est une vue schématique en élévation du poste blindé selon l'invention, les appareils de coupure et de sectionnement étant représentés en position d'ouverture;
• la figure 2 représente une vue en plan de la figure 1, montrant deux travées adjacentes du poste;
• la figure 3 montre le schéma électrique unifilaire de la travée selon la figure 1;
• la figure 4 représente le schéma électrique unifilaire d'une variante de réalisation.

Other advantages will emerge more clearly from the description which follows of two embodiments given by way of nonlimiting examples, and represented in the appended drawings in which:

• Figure 1 is a schematic elevational view of the shielded post according to the invention, the switching and cutting devices being shown in the open position;
• Figure 2 shows a plan view of Figure 1 showing two adjacent spans of the substation;
• Figure 3 shows the single-wire electrical diagram of the span according to Figure 1;
• FIG. 4 represents the single-wire electrical diagram of an alternative embodiment.

In Figures 1 to 3, an armored distribution station high voltage has a metal casing 10 grounded, and filled with a stiff gas high dielectric, especially hexafluoride sulfur under pressure. The station is equipped with a plurality of spans 12,12a, (two are shown on Figure 2), staggered at regular intervals on along first and second busbars 14.16 supply, each bay 12.12a containing specific electrical switchgear, sectioning and connection associated with a departure 18.

Each busbar 14, 16 is housed in a 19 cylindrical enclosure forming part of the envelope 10 metallic, and comprises three bars 20,22,24; 26,28,30 conductors of three-phase supply. The two busbars 14,16 are superimposed in the direction of the height, and the spans 12,12a are on the same side of the enclosure 19.

The metallic envelope 10 of each span 12,12a is subdivided into different compartments formed by elementary sections or caissons tightly connected to each other by bndes or connection ends, with interposition support insulators 32 forming the partitioning between the adjacent compartments. The support insulators 32 are crossed by the bars and electrical conductors of electrical connection elements of the apparatus contained in the compartments.

Each bay 12,12a has a circuit breaker three-pole 34 housed in a circuit breaker compartment 36 having three connection ends, respectively to a measuring compartment 38 on the side left, and with two busbar compartments 40.42 superimposed on the right side. The measurement compartment 38 contains a three-phase current transformer 44 and a three-phase earthing switch 46.

The associated upper 40 busbar compartment in the first busbar 14 additionally contains three busbars 20,22,24 supply electric, a first three-phase switch disconnector 45 intended to ensure the electrical connection of the circuit breaker 34 at the corresponding bars 20,22,24 in the closed position, and the electrical isolation in open position. The switch disconnector 45 is slidably actuated by a mechanism control 48 fixed to the external compartment flange 40, while the opposite connection flange to the circuit breaker compartment 36 carries the fixed contacts of the switch disconnector 45 including the movable pins (not shown) operated by the insulating rods 49 extend perpendicular to the bars feed 20,22,24.

The composition of the bar set compartment 42 lower is identical to that of the upper compartment 40, and is equipped with a second three-phase disconnector switch 47 (see Figure 3) associated with second busbar 16, and controlled by a mechanism 50 (Figure 1).

The measurement compartment 38 is interposed between the circuit breaker compartment 36 and a compartment disconnector 52 containing a disconnector three-phase line 54 activated by a mechanism control 56. The outgoing cables 18 are connected to a connection compartment 58 containing a three-phase cable box 60 and a disconnector three-phase earthing 62 controlled by a mechanism 64. The connection compartment 58 is placed under the sectioning compartment 52, and rests on the base 64 via a fixed mechanical support 66.

On the intermediate part of the base 64 rests also the circuit breaker control box 67 34. The poles of the latter extend vertically inside the circuit breaker compartment 36, which additionally contains a three-phase earthing switch the earth 68. The electrical connection device 70 common between the three-pole circuit breaker 34 and the two switch disconnectors 45.47 associated with both busbars 14,16, is housed in the compartment circuit breaker 36 extending parallel to the poles of circuit breaker 34. The lower part of the connection 70 is equipped with three fixed contacts 72 cooperating with the corresponding movable pins of the three-phase earthing switch 68.

74.76 three-phase earthing switch (see Figures 2 and 3) is associated on the other hand with each busbar 14.16 to ensure the earthing of the corresponding bars 20,22,24; 26,28,30.

The closure of one of the switch disconnectors 45.47 allows to feed each span 12.12a respectively by the first or the second set of bars 14,16, the circuit breaker 34 providing protection from the start 18. In the event of a failure or the setting off for repair of one of the bars 14,16, the spans 12,12a can be supplied by the other busbar to maintain continuity on duty.

We notice that at the level of each span 12,12a, the distribution of the release disconnectors earth 74,76,68,46,62 along the electrical circuit is such as each breaking or cutting device 45,47,34,54 is supervised by two disconnectors of earthing.

The earthing switch 68 placed inside circuit breaker compartment 36 cannot be isolated, given the permanent electrical connection of its movable pins with the mass of the envelope 10 to the potential of the earth. On the other hand, the disconnector of earthing 46 of the measuring compartment 38 and earthing switches 74,76 bars 14,16 are isolable, i.e. they have at each phase, a test terminal isolated fitted with a disconnectable electrical connection with the earth. The isolation function of the disconnectors 74,76,46 is shown schematically in Figure 3 by dotted lines.

The non-isolatable arrangement of the terre 68 reduces the cost of invoicing of the circuit breaker compartment 36.

This ability to isolate certain disconnectors earthing allows various tests to be carried out on each span 12,12a. After prior opening two switch disconnectors 45,47, allowing to isolate the corresponding bay 12,12a from the two busbars 14,16, the circuit breaker response time 34 can be easily measured by injecting a test signal in the isolated test terminals of the disconnector 46 in the closed position. The circuit breaker 34 and the earthing switch 68 are previously closed, and the line disconnector 54 is open. The test current flows from the test terminals to earth at through circuit breaker 34 and the disconnect switch the earth 68. It is also possible by this same circuit to verify the characteristics of the transformer current 44, in particular the transformation ratio, by injecting a current through the disconnector 46 low voltage test, of a similar intensity of the nominal intensity of the span 12,12a. This current travels through the primary circuit of the transformer current 44, and it is enough to measure the secondary voltages to deduce the transformation ratio.

The measurement of voltage drops of the main circuit of each span 12,12a also makes it possible to check the good condition of the internal connections and the resistors of the different sections. This verification operates by injecting a direct current, having a current of the order of 100A, in the isolated terminals disconnectors 46,74,76. For measuring the fall voltage in the line disconnector circuit 54, simply open the circuit breaker 34, close the line disconnector 54 and earthing switch 62 compartments 52,58, and inject the test current by isolatable disconnector 46. For the measurement of voltage drop in circuit breaker 34 it line 54 and switch disconnectors must be opened 45,47, close the circuit breaker 34 and the circuit breaker earth 68 in compartment 36, and inject the test current through isolatable disconnector 46. The measurement of the voltage drop in the circuit of the first switch disconnector 45 and the device connection 70 with circuit breaker 34, takes place after busbar 14 switched off followed by opening of circuit breaker 34 and second disconnector switch 47, closing the disconnector of earthing 68 and injection of the test current by isolatable disconnector 74 from the first set of bars 14. The measurement of the voltage drop in the second switch disconnector circuit 47 operates in an equivalent manner, after switching off busbar 16, followed by opening of the circuit breaker 34 and the first switch disconnector 45, the closing of the earthing switch 68, and injection of the test current by the disconnector 76 isolable.

The invention has been described as being applied to a three-phase substation whose three phases are contained in a single envelope, but it stretches of course at stations with separate phases, each phase having its own earthed enclosure. The architecture of the station can be modified, in particular more spans, and the layout of the circuit breaker compartment with respect to 40.42 busbar and connection compartment 58. The electrical diagram in Figure 4 shows extension of the invention to any three-phase shielded substation or single-phase, in which a switching device and of disconnection 100, in particular a circuit breaker, a line switch or disconnector or switch is supervised by two disconnect switches earthing 102,104 of which one 102 is isolable, and the other 104 cannot be isolated.

In Figure 3, the earthing switch 62 is shown not isolable, but it could also be isolable according to the type of architecture of the span.

Claims (4)

1. A high voltage metalclad substation having an earthed metallic enclosure (10) filled with a high dielectric strength insulating gas, said enclosure being subdivided in each bay (12, 12a) into different airtight compartments acting as housing for the equipment arranged in the electrical circuit between a supply busbar (14, 16) and a feeder (18), each breaking and/or disconnecting apparatus (54, 34, 45, 47, 100) being bracketed by two earthing switches, characterized in that one of the earthing switches (46, 74, 76, 102) is isolatable whereas the other earthing switch (68, 62, 104) is non-isolatable, the isolatable earthing switch (46, 74, 76, 102) comprising an isolated test terminal and an electrical connection disconnectable with the earth, and that the circuit breaker compartment (36) of each bay (12) contains a circuit breaker (34) and a non-isolatable earthing switch (68) having movable grips co-operating with a system of stationary contacts (72) securedly united to a connection device (70) for connecting the circuit breaker (34) with the supply busbar (14, 16).
2. The metalclad substation according to claim 1, characterized in that the circuit breaker compartment (36) is inserted between a measurement compartment (38) housing a current transformer (44) and two superposed busbar compartments (40, 42) each containing a switching disconnector (45, 47) for connection of the circuit breaker (34) either to a first busbar (14) or to a second busbar (16), and that an isolatable earthing switch (46) is housed in the measurement compartment (38).
3. The metalclad substation according to claim 2, characterized in that an isolatable earthing switch (74, 76) is associated to each busbar (14, 16).
4. The metalclad substation according to claim 3, characterized in that a disconnection compartment (52) houses a line disconnector (54) inserted between the isolatable earthing switch (46) of the measurement compartment (38) and a cable box (60) housed in a connection compartment (58) of the feeder (18).

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